Introduce skipForcedClientInitialization property.

Fixes spring-cloudgh-4152

spring-cloud-netflix-eureka-client/src/main/java/org/springframework/cloud/netflix/eureka/EurekaClientAutoConfiguration.java

@@ -224,8 +224,8 @@ private void setupJmxPort(EurekaInstanceConfigBean instance, Integer jmxPort) {
 	}
 
 	@Bean
-	public EurekaServiceRegistry eurekaServiceRegistry() {
-		return new EurekaServiceRegistry();
+	public EurekaServiceRegistry eurekaServiceRegistry(EurekaInstanceConfigBean eurekaInstanceConfigBean) {
+		return new EurekaServiceRegistry(eurekaInstanceConfigBean);
 	}
 
 	// @Bean

spring-cloud-netflix-eureka-client/src/main/java/org/springframework/cloud/netflix/eureka/EurekaInstanceConfigBean.java

@@ -269,6 +269,12 @@ public class EurekaInstanceConfigBean implements CloudEurekaInstanceConfig, Envi
 	 */
 	private boolean preferIpAddress = false;
 
+	/**
+	 * If true the EurekaClient will not be forced to initialize when the InstanceRegistry
+	 * bean is created.
+	 */
+	private boolean skipForcedClientInitialization;
+
 	/**
 	 * Initial status to register with remote Eureka server.
 	 */
@@ -547,6 +553,14 @@ public void setPreferIpAddress(boolean preferIpAddress) {
 		this.preferIpAddress = preferIpAddress;
 	}
 
+	public boolean isSkipForcedClientInitialization() {
+		return skipForcedClientInitialization;
+	}
+
+	public void setSkipForcedClientInitialization(boolean skipForcedClientInitialization) {
+		this.skipForcedClientInitialization = skipForcedClientInitialization;
+	}
+
 	public InstanceStatus getInitialStatus() {
 		return initialStatus;
 	}
@@ -597,6 +611,7 @@ public boolean equals(Object o) {
 				&& Objects.equals(namespace, that.namespace) && Objects.equals(hostname, that.hostname)
 				&& preferIpAddress == that.preferIpAddress && Objects.equals(initialStatus, that.initialStatus)
 				&& Arrays.equals(defaultAddressResolutionOrder, that.defaultAddressResolutionOrder)
+				&& skipForcedClientInitialization == that.skipForcedClientInitialization
 				&& Objects.equals(environment, that.environment);
 	}
 
@@ -607,7 +622,8 @@ public int hashCode() {
 				leaseExpirationDurationInSeconds, virtualHostName, instanceId, secureVirtualHostName, aSGName,
 				metadataMap, dataCenterInfo, ipAddress, statusPageUrlPath, statusPageUrl, homePageUrlPath, homePageUrl,
 				healthCheckUrlPath, healthCheckUrl, secureHealthCheckUrl, namespace, hostname, preferIpAddress,
-				initialStatus, Arrays.hashCode(defaultAddressResolutionOrder), environment);
+				skipForcedClientInitialization, initialStatus, Arrays.hashCode(defaultAddressResolutionOrder),
+				environment);
 	}
 
 	@Override
@@ -631,6 +647,7 @@ public String toString() {
 				.append("', ").append("healthCheckUrl='").append(healthCheckUrl).append("', ")
 				.append("secureHealthCheckUrl='").append(secureHealthCheckUrl).append("', ").append("namespace='")
 				.append(namespace).append("', ").append("hostname='").append(hostname).append("', ")
+				.append("skipForcedClientInitialization=").append(skipForcedClientInitialization).append(", ")
 				.append("preferIpAddress=").append(preferIpAddress).append(", ").append("initialStatus=")
 				.append(initialStatus).append(", ").append("defaultAddressResolutionOrder=")
 				.append(Arrays.toString(defaultAddressResolutionOrder)).append(", ").append("environment=")

spring-cloud-netflix-eureka-client/src/main/java/org/springframework/cloud/netflix/eureka/serviceregistry/EurekaServiceRegistry.java

@@ -23,6 +23,8 @@
 import org.apache.commons.logging.LogFactory;
 
 import org.springframework.cloud.client.serviceregistry.ServiceRegistry;
+import org.springframework.cloud.netflix.eureka.CloudEurekaClient;
+import org.springframework.cloud.netflix.eureka.EurekaInstanceConfigBean;
 
 import static com.netflix.appinfo.InstanceInfo.InstanceStatus.UNKNOWN;
 
@@ -33,6 +35,12 @@ public class EurekaServiceRegistry implements ServiceRegistry<EurekaRegistration
 
 	private static final Log log = LogFactory.getLog(EurekaServiceRegistry.class);
 
+	private final EurekaInstanceConfigBean eurekaInstanceConfigBean;
+
+	public EurekaServiceRegistry(EurekaInstanceConfigBean eurekaInstanceConfigBean) {
+		this.eurekaInstanceConfigBean = eurekaInstanceConfigBean;
+	}
+
 	@Override
 	public void register(EurekaRegistration reg) {
 		maybeInitializeClient(reg);
@@ -51,7 +59,14 @@ public void register(EurekaRegistration reg) {
 	private void maybeInitializeClient(EurekaRegistration reg) {
 		// force initialization of possibly scoped proxies
 		reg.getApplicationInfoManager().getInfo();
-		reg.getEurekaClient().getApplications();
+
+		CloudEurekaClient eurekaClient = reg.getEurekaClient();
+
+		if (eurekaInstanceConfigBean.isSkipForcedClientInitialization()) {
+			eurekaClient.getEurekaClientConfig();
+		} else {
+			eurekaClient.getApplications();
+		}
 	}
 
 	@Override

spring-cloud-netflix-eureka-client/src/test/java/org/springframework/cloud/netflix/eureka/serviceregistry/EurekaServiceRegistryTests.java

@@ -21,9 +21,13 @@
 import com.netflix.appinfo.ApplicationInfoManager;
 import com.netflix.appinfo.InstanceInfo;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
 
 import org.springframework.cloud.commons.util.InetUtils;
 import org.springframework.cloud.commons.util.InetUtilsProperties;
+import org.springframework.cloud.loadbalancer.support.SimpleObjectProvider;
 import org.springframework.cloud.netflix.eureka.CloudEurekaClient;
 import org.springframework.cloud.netflix.eureka.EurekaClientConfigBean;
 import org.springframework.cloud.netflix.eureka.EurekaInstanceConfigBean;
@@ -34,18 +38,23 @@
 import static com.netflix.appinfo.InstanceInfo.InstanceStatus.UNKNOWN;
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.verifyNoInteractions;
 import static org.mockito.Mockito.when;
 
 /**
  * @author Spencer Gibb
  * @author Tim Ysewyn
  */
+@ExtendWith(MockitoExtension.class)
 class EurekaServiceRegistryTests {
 
+	@Mock
+	private EurekaInstanceConfigBean eurekaInstanceConfigBean;
+
 	@Test
 	void eurekaClientNotShutdownInDeregister() {
-		EurekaServiceRegistry registry = new EurekaServiceRegistry();
+		EurekaServiceRegistry registry = new EurekaServiceRegistry(eurekaInstanceConfigBean);
 
 		CloudEurekaClient eurekaClient = mock(CloudEurekaClient.class);
 		ApplicationInfoManager applicationInfoManager = mock(ApplicationInfoManager.class);
@@ -65,7 +74,7 @@ void eurekaClientNotShutdownInDeregister() {
 	@SuppressWarnings("unchecked")
 	@Test
 	void eurekaClientGetStatus() {
-		EurekaServiceRegistry registry = new EurekaServiceRegistry();
+		EurekaServiceRegistry registry = new EurekaServiceRegistry(eurekaInstanceConfigBean);
 
 		EurekaInstanceConfigBean config = new EurekaInstanceConfigBean(new InetUtils(new InetUtilsProperties()));
 		config.setAppname("myapp");
@@ -102,16 +111,14 @@ void eurekaClientGetStatus() {
 	@SuppressWarnings("unchecked")
 	@Test
 	void eurekaClientGetStatusNoInstance() {
-		EurekaServiceRegistry registry = new EurekaServiceRegistry();
+		EurekaServiceRegistry registry = new EurekaServiceRegistry(eurekaInstanceConfigBean);
 
 		EurekaInstanceConfigBean config = new EurekaInstanceConfigBean(new InetUtils(new InetUtilsProperties()));
 		config.setAppname("myapp");
 		config.setInstanceId("1234");
 
 		CloudEurekaClient eurekaClient = mock(CloudEurekaClient.class);
 
-		when(eurekaClient.getInstanceInfo("myapp", "1234")).thenReturn(null);
-
 		ApplicationInfoManager applicationInfoManager = mock(ApplicationInfoManager.class);
 		when(applicationInfoManager.getInfo()).thenReturn(mock(InstanceInfo.class));
 
@@ -130,4 +137,43 @@ void eurekaClientGetStatusNoInstance() {
 		assertThat(map).hasSize(1).containsEntry("status", UNKNOWN.toString());
 	}
 
+	@Test
+	void eurekaClientDoesNotForceInitialization() {
+		when(eurekaInstanceConfigBean.isSkipForcedClientInitialization()).thenReturn(true);
+		EurekaServiceRegistry registry = new EurekaServiceRegistry(eurekaInstanceConfigBean);
+
+		CloudEurekaClient eurekaClient = mock(CloudEurekaClient.class);
+		ApplicationInfoManager applicationInfoManager = mock(ApplicationInfoManager.class);
+
+		when(applicationInfoManager.getInfo()).thenReturn(mock(InstanceInfo.class));
+
+		EurekaRegistration registration = EurekaRegistration
+				.builder(new EurekaInstanceConfigBean(new InetUtils(new InetUtilsProperties()))).with(eurekaClient)
+				.with(applicationInfoManager).with(new EurekaClientConfigBean(), mock(ApplicationEventPublisher.class))
+				.with(new SimpleObjectProvider<>(null)).build();
+
+		registry.register(registration);
+
+		verifyNoInteractions(eurekaClient);
+	}
+
+	@Test
+	void eurekaClientDoesForceInitialization() {
+		EurekaServiceRegistry registry = new EurekaServiceRegistry(eurekaInstanceConfigBean);
+
+		CloudEurekaClient eurekaClient = mock(CloudEurekaClient.class);
+		ApplicationInfoManager applicationInfoManager = mock(ApplicationInfoManager.class);
+
+		when(applicationInfoManager.getInfo()).thenReturn(mock(InstanceInfo.class));
+
+		EurekaRegistration registration = EurekaRegistration
+				.builder(new EurekaInstanceConfigBean(new InetUtils(new InetUtilsProperties()))).with(eurekaClient)
+				.with(applicationInfoManager).with(new EurekaClientConfigBean(), mock(ApplicationEventPublisher.class))
+				.with(new SimpleObjectProvider<>(null)).build();
+
+		registry.register(registration);
+
+		verify(eurekaClient).getApplications();
+	}
+
 }

spring-cloud-netflix-eureka-server/src/main/java/org/springframework/cloud/netflix/eureka/server/EurekaServerAutoConfiguration.java

@@ -88,6 +88,7 @@
 import org.springframework.cloud.client.actuator.HasFeatures;
 import org.springframework.cloud.context.environment.EnvironmentChangeEvent;
 import org.springframework.cloud.netflix.eureka.EurekaConstants;
+import org.springframework.cloud.netflix.eureka.EurekaInstanceConfigBean;
 import org.springframework.context.ApplicationListener;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.ClassPathScanningCandidateComponentProvider;
@@ -207,8 +208,12 @@ public Jersey3DiscoveryClientOptionalArgs jersey3DiscoveryClientOptionalArgs() {
 
 	@Bean
 	public PeerAwareInstanceRegistry peerAwareInstanceRegistry(ServerCodecs serverCodecs,
-			EurekaServerHttpClientFactory eurekaServerHttpClientFactory) {
-		this.eurekaClient.getApplications(); // force initialization
+			EurekaServerHttpClientFactory eurekaServerHttpClientFactory,
+			EurekaInstanceConfigBean eurekaInstanceConfigBean) {
+		if (!eurekaInstanceConfigBean.isSkipForcedClientInitialization()) {
+			this.eurekaClient.getApplications(); // force initialization
+		}
+
 		return new InstanceRegistry(this.eurekaServerConfig, this.eurekaClientConfig, serverCodecs, this.eurekaClient,
 				eurekaServerHttpClientFactory,
 				this.instanceRegistryProperties.getExpectedNumberOfClientsSendingRenews(),

spring-cloud-netflix-eureka-server/src/test/java/org/springframework/cloud/netflix/eureka/server/EurekaServerAutoConfigurationTests.java

@@ -0,0 +1,87 @@
+/*
+ * Copyright 2013-2022 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.cloud.netflix.eureka.server;
+
+import com.netflix.discovery.EurekaClient;
+import com.netflix.discovery.EurekaClientConfig;
+import com.netflix.eureka.EurekaServerConfig;
+import com.netflix.eureka.resources.ServerCodecs;
+import com.netflix.eureka.transport.EurekaServerHttpClientFactory;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.InjectMocks;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+
+import org.springframework.cloud.netflix.eureka.EurekaInstanceConfigBean;
+
+import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+@ExtendWith(MockitoExtension.class)
+class EurekaServerAutoConfigurationTests {
+
+	@Mock
+	private EurekaServerConfig eurekaServerConfig;
+
+	@Mock
+	private EurekaClientConfig eurekaClientConfig;
+
+	@Mock
+	private EurekaClient eurekaClient;
+
+	@Mock
+	private InstanceRegistryProperties instanceRegistryProperties;
+
+	@Mock
+	private ServerCodecs serverCodecs;
+
+	@Mock
+	private EurekaServerHttpClientFactory eurekaServerHttpClientFactory;
+
+	@Mock
+	private EurekaInstanceConfigBean eurekaInstanceConfigBean;
+
+	@InjectMocks
+	private EurekaServerAutoConfiguration eurekaServerAutoConfiguration;
+
+	@BeforeEach
+	void setup() {
+		when(eurekaServerConfig.getDeltaRetentionTimerIntervalInMs()).thenReturn(1L);
+	}
+
+	@Test
+	void shouldForceEurekaClientInit() {
+		eurekaServerAutoConfiguration.peerAwareInstanceRegistry(serverCodecs, eurekaServerHttpClientFactory,
+				eurekaInstanceConfigBean);
+
+		verify(eurekaClient).getApplications();
+	}
+
+	@Test
+	void shouldNotForceEurekaClientInit() {
+		when(eurekaInstanceConfigBean.isSkipForcedClientInitialization()).thenReturn(true);
+
+		eurekaServerAutoConfiguration.peerAwareInstanceRegistry(serverCodecs, eurekaServerHttpClientFactory,
+				eurekaInstanceConfigBean);
+
+		verify(eurekaClient, never()).getApplications();
+	}
+
+}